a personal-public notebook about human development(s) ... by michaela raab

Friday, 26 June 2009

Quantitative is qualitative, too...

Yesterday I read an advertisement for a body lotion scientifically proven* to better the skin of 80% of lotion users. The *footnote explained that, in a trial bringing together twenty women, 80% stated the lotion made their skin feel smoother. Does that sound scientific enough? In any case, it illustrates how you turn qualitative judgements (respondents' reported feelings) into "hard" figures, a procedure which as such is not "manipulative" but established scientific practice.
As a matter of fact, qualitative judgements are at the roots of all quantitative measurement, even in natural sciences: you need to decide what exactly you want to measure and determine how to establish a scale before you can start counting. When Swedish astronomer Anders Celsius developed his temperature scale (1742), he based it on the qualitative observation that water evaporated when heated and solidified when cooled. Then he established a scale which put the boiling point at 0 and the freezing point at 100 (no typing mistake - the original Celsius scale is the reverse of what you find on today's thermometers). He decided that the intervals on the scale would be equal. There could have been other solutions: for example, the Richter magnitude scale, used to measure seismic energy released in earthquakes, is logarithmic: point 5 on the Richter scale comes with a shaking magnitude that is ten times stronger than at point 4.

Qualitative analysis establishes concepts, categories and instruments for measuring. Only after all this qualitative work is done, you can take your quantitative measurement: you look at the thermometer and you read 28°C. If you're a big fan of quantitative indicators, enjoy this moment, because it is brief, as the analysis that follows will be qualitative: is 28°C hot, warm, mild, cool or a bit chilly?

Back on-line!

Apologies to all those who have tried to post comments since mid-2017! I have been too terribly busy to review and authorise the comments in good time. (This blog is a free-time venture after all.)

Meanwhile, the European Commission's General Data Protection Regulation has come into force and it has become complicated to display comments. To stay on the safe side, I have deleted all comments ever posted to this blog. I am very sorry about that, because I have enjoyed this form of conversation. And I do hope you will enjoy reading future posts all the same.

About me

I am a consultant with some 30 years of experience in development - in particular, monitoring & evaluation, facilitation, training and applied research with a range of organisations and in many places around the world. I live in Berlin and work in several languages.This blog is a free time venture - so please bear with typos and occasional long waits between the posts.

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